Script to download files in a async way, using Python asyncio

async_download_files.py

import os
import asyncio
import aiohttp  # pip install aiohttp
import aiofile  # pip install aiofile

REPORTS_FOLDER = "reports"
FILES_PATH = os.path.join(REPORTS_FOLDER, "files")


def download_files_from_report(urls):
    os.makedirs(FILES_PATH, exist_ok=True)
    sema = asyncio.BoundedSemaphore(5)

    async def fetch_file(session, url):
        fname = url.split("/")[-1]
        async with sema:
            async with session.get(url) as resp:
                assert resp.status == 200
                data = await resp.read()

        async with aiofile.async_open(
            os.path.join(FILES_PATH, fname), "wb"
        ) as outfile:
            await outfile.write(data)

    async def main():
        async with aiohttp.ClientSession() as session:
            tasks = [fetch_file(session, url) for url in urls]
            await asyncio.gather(*tasks)

    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())
    loop.close()

Great piece of code!

You should refactor to reuse the session, not creating one for each request.

applied suggestions

Very elegant solution but after experimenting with it for a while, I have started getting errors while downloading files (never the same file and if you try enough times, the downloads for all files succeed):

aiohttp.client_exceptions.ClientPayloadError: Response payload is not completed

Is the solution to change the code to catch that exception and try N times before giving up or is the root cause known?

Very elegant solution but after experimenting with it for a while, I have started getting errors while downloading files (never the same file and if you try enough times, the downloads for all files succeed):

aiohttp.client_exceptions.ClientPayloadError: Response payload is not completed

Is the solution to change the code to catch that exception and try N times before giving up or is the root cause known?

Please check aiohttp documentation about ClientPayloadError and yes, you can use aiohttp-retry to handle the failure cases

does this not work for video files?I am getting error 403.